It is possible to run PHP in suexec CGI mode, there is no dedicated configuration for this but it can be done with some simple rewrite rules to simulate Apache's "Hanlder" directive. I will post the rewrite rule later.

Anyway, running PHP as CGI does not give the best performance.
It is not possible to do that with lsphp yet, it is on our to do list.

I've read through a couple posts regarding running PHP suExec through fastcgi interface, and what I understand is that it's currently not possible in a straightforward way. However, you suggested that it's possible to do so if we provide dedicated php-fcgi process for each UID. How exactly do we do that?

I've running such a setup with lighttpd with great success bar some sites canot be run there since due to some complications in its rewrite enginge--so I decide to give litespeed a try. So far so good, except I need to run php in suExec way.